1. Field of Invention
The present invention relates to an electric motor structure applicable to electrical equipment to be mounted on motor vehicles.
2. Description of Related Art
In general, an electric motor of this kind is equipped with a yoke containing an armature shaft therein and a base unit including a brush holder, and the yoke is designed to be connected to a bracket such as an end bracket by a set bolt which penetrates the base unit in its axial direction. Further, in this type of electric motor, a pair of internal terminals respectively connected to brushes are provided on the base unit, and a coupler with external terminals penetrates into the interior of the yoke from the exterior of the yoke to establish an electrical connection between the interior and the exterior of the yoke.
However, in this case, there is a need to arrange the various components taking into consideration insulation between the set bolt and the respective members placed in the base unit and the mounting of the respective members. For this reason, in a related motor, as shown in FIG. 7, the layout is designed so that the facing line between a pair of set bolts 10e at the positions where the set bolts penetrate the base unit, is substantially perpendicular to a facing line between a pair of brushes at the positions where the brushes are disposed on the base unit, and internal terminal plates 18c mounted on the base unit 17 are placed between the penetration position of the one set bolt 10e and a brush holder 11.
However, in this structure, the facing distances between the brushes 18 and the corresponding internal terminal plates 18c differ from each other, and accordingly, it is necessary to prepare two types of brushes having pigtails 18b different in length. The longer pigtail 18b requires wiring to run over a set bolt 10e, and hence, measures must be taken to electrically insulate the set bolt, so the number of parts increases and the working efficiency deteriorates. The Applicant's invention is intended to solve the aforementioned problems with the prior art.